title: Small cell variant of anaplastic large cell lymphoma with positive immunoreactivity for CD99.
abstract: A 13 year old boy presented with a huge mass on his right arm of 6 months duration. Histopathological examination revealed sheets of malignant small round blue cells with immunopositivity for LCA, CD43, CD45Ro, CD30, EMA, ALK-1 and CD99, and negativity for CD20, TdT, myogenin, myoD1, NSE, bcl-6, bcl-2 and CD10. Fluorescent In-Situ Hybridization (FISH) testing excluded the diagnosis of Ewing's sarcoma/PNET. Pathologists need to be aware of the diagnosis of a small cell variant of ALCL, as well as of the fact that CD99 expression commonly occurs in cases of ALK-positive ALCL, in order to distinguish this entity from Ewing's sarcoma/PNET.
authors.affiliation: Department of Pathology, Universiti Putra Malaysia, Serdang, Malaysia. mshiran@yahoo.com
authors.forename: M S
authors.initials: MS
authors.lastname: Shiran
authors.forename: G C
authors.initials: GC
authors.lastname: Tan
authors.forename: A R
authors.initials: AR
authors.lastname: Sabariah
authors.forename: P C
authors.initials: PC
authors.lastname: Chye
authors.forename: R
authors.initials: R
authors.lastname: Pathmanathan
mesh_terms: D000071443:12E7 Antigen; D000293:Adolescent; D015703:Antigens, CD / Q000276:immunology*; D001132:Arm; D015815:Cell Adhesion Molecules / Q000276:immunology*; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000276:immunology* / Q000473:pathology; D008297:Male; D012983:Soft Tissue Neoplasms / Q000276:immunology* / Q000473:pathology
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules